Pontarachna ivonae, Pešić, Vladimir, 2013

Pešić, Vladimir, 2013, Pontarachnid mites from marine interstitial, with a description of three new species from South Korea (Acari: Hydrachnidia: Pontarachnidae), Zootaxa 3701 (1), pp. 83-92 : 89-91

Pontarachna ivonae sp. nov.

( Figs. 2A–C , 5A–L)

Type series. Holotype male (NIBRIV0000268892), dissected and slide mounted in Hoyer's fluid, South Korea, Wido Island, beech, 35º35.089' N, 126º 15.196' E, interstitial, 12.iv.2013 Karanović. Paratypes: two females, Yellow Sea, Wido Island, Seokgeum beach, 35º34.117' N, 126º 06.009' E, interstitial, sample #27, 13.iv.2013 Karanović, one female dissected and slide mounted (NIBRIV0000268893); one female, East Sea, Gangneung beach, sample #5, 37º47.824' N, 128º 55.085' E, 29.iii.2013 Karanović, fixed in Koenike fluid; East Sea, Yeondeok, beach, sample #12, littoral, 36º21.830' N, 129º 23.657' E, 30.iii.2013 Karanović, two males and one female dissected and slide mounted in Hoyer's fluid, two females and one male fixed in Koenike fluid, 12 adults conserved in alcohol (MNHP).

Diagnosis. Posterior margin of Cx-IV with two pairs of short and broad apodemes; the lateral ones slightly larger than medial ones; sclerotized area of genital field in male with 6–7 pairs of setae. Additionaly 1–2 pairs may lie free in the integument, touching anterior margin of the genital field.

Description. Male (holotype, in parentheses from Yeondeok, n = 2): Integument soft, ocular pigment well developed ( Figs. 2A–C ). Idiosoma L/W 313 (365–391)/195 (242–300). Coxal field: L/W 151 (165–166)/168 (193– 200); Cx-I separated medially; suture lines Cx-II/III incomplete; posterior margin of Cx-IV strongly concave, with two pairs of short and broad apodemes; the lateral ones slightly larger than medial ones; the latter extending beyond anterior margin of the genital field (Fig. 5A). Genital field L/W 32 (33–34)/25 (26–26), consisting of a sclerotized ring with 6–7 pairs of setae; one to two perigenital seate on each side may lie free in the integument closely approaching or touching anterior margin of genital field. Directly posteriorly of Cx-IV two glandulariumlike structures, accompanied by a seta. Posterior to the genital field two pairs of wheel-like acetabula, these on a common platelet on their respective sides. Near posterior margin of idiosoma a glandularium like structura accompanied by two setae. Excretory pore unsclerotized. Gnathosoma (Fig. 5C) vL 87 (91–93); chelicerae FIGURE 5A – L. Pontarachna ivonae sp. nov. (A, C–D, F, I–L = male [A, C–D, F, I, L = holotype, F, K - specimen from Yendeok], B, E, G–H = female [B, E, H—specimen from Wido Island, G – specimen from Yendeok]): A – B = idiosoma, ventral view; C = palp and gnathosoma; D = I-L-3–6; E = I-L-5–6; F – G = genital field; H = palp; I = chelicerae; K = claw of II-L; L = IV-L-4–6. Scale bars = 100 µm.

stilletiform (Fig. 5I) total L 194 (242). Palp (Fig. 5C) total L 173 (183–184), dL/H, L/H ratio: P-1, 14/17, 0.82 (13– 14/17–18.5, 0.7–0.82); P-2, 42/27, 1.53 (44–46/28–31, 1.5–1.59); P-3, 43/25, 1.7 (41–42/28, 1.47–1.52); P-4, 55/ 14, 4.0 (60–62/17, 3.55–3.62); P-5, 20/7, 2.9 (22–23/8, 2.8–3.0); dL P-2/P-4 ratio 0.75 (0.72–0.77); P-2 with straight or slightly concave ventral and convexly bowed dorsal margin; P-3 ventral margin straight; P-4 slender, basally thickened, from here to anterior tip narrowed. Legs: dL of I-L-2–6 (Fig. 5D): (32–37), 39 (41–42), 39 (45– 46), 54 (55–57), 66 (71–74); I-L-6 H 23 (23–25), I-L-6 dL/H ratio 2.9 (2.9–3.1); dL of IV-L-2–6 (Fig. 5L): (39– 42), (44–48), 65 (69), 86 (89–92), 72 (77–78); III-L-5 with one swimming seta; IV-L-5 with one swimming seta.

Female (from Genyneung beach, in parentheses from Yeondeok, n = 1): Similar to male, except for the shape of the genital field (Fig. 5B). Idiosoma L/W 352 (389)/234 (258). Coxal field: L/W 162 (163)/191 (200); medial posterior apodemes of Cx-IV not extending beyond posterior margin of genital field. Genital field L/W 55 (61)/28 (28); pregenital sclerite strongly bowed, L 25 (28); postgenital sclerite slightly bowed, with a pair of wheel-like acetabula, L 28 (28). Posterior to the genital field two additional pairs of wheel-like acetabula, these on a common platelet on their respective sides. Gnathosoma vL 89. Palp (Fig. 5H): total L 177–179 (188), dL/H, L/H ratio: P-1, 14/18, 0.79 (14/19, 0.74); P-2, 43/28, 1.55 (46/31, 1.5); P-3, 45/28, 1.6 (44/29, 1.5); P-4, 55–57/17, 3.4 (63/17, 3.7); P-5, 20/8, 2.6 (21/8, 2.7); dL P-2/P-4 ratio 0.75–0.78 (0.73); palp as in male. Legs: dL of I-L-2–6: 37 (35), 42 (45), 43 (49), 59 (60), 69 (72); I-L-6 H 21.5 (24), I-L-6 dL/H ratio 3.2 (3.0); dL of IV-L: (52), (42), (48), 71 (72), 85–86 (92), 75 (79); number of swimming setae as in the male.

Etymology. The species is named after Ivona Pešić, the seven-year old daughter of the author.

Remarks. The lower number of setae in the sclerotized area of the genital field in male, the lateral posterior apodemes of Cx-IV longer than medial ones, and the similar configuration of the wheel-like acetabula, make the new species similar to Pontarachna erythraea K.O. Viets, 1966 , a species known from the Red Sea (K.O. Viets 1966). However, in the latter species a sclerotized area of the genital field lacking and the 7–8 setae are situated in a row medial and anterior to the genital field.

Distribution. South Korea (Yellow Sea and East Sea).

Figures

FIGURE 2 A – H. Photographs of the dorsum. A – C Pontarachna ivonae sp. nov.: A – B – specimens from Wido Island, interstitial; C – specimen from Yeondeok, littoral. D Litarachna lukai sp. nov., holotype. E – F Litarachna gracilis sp. nov., female holotype. G – H Litarachna cf. denhami (Lohmann, 1909), female, Gupyeong-ri, South Korea, littoral.